How to build a Yamaha SR500 street tracker, the Mule way

We know Richard Pollock is a master of his craft—and we know he’s thorough. But we’re beginning to think he’s a little obsessive. This Yamaha SR500 went onto the Mule Motorcycles bench for some basic upgrades. But as Richard dug deeper, he found more and more issues. Things snowballed fast…

“The bike was an ex-road racer converted to a street tracker, that had a bad idle” he says. “It fitted a very common profile: a race bike that had been to hell and back (maybe even making repeated trips), and was severely worn from end to end.”

Despite the state of the SR500, Richard really liked its basic theme—just not the execution. “All the right intentions … but the puzzle was just assembled all wrong,” he tells us.

“The bars were a weird bend, the wheels had skinny tires, the XR750-style seat was mounted too far back and felt like it was made of steel, the pipe hung too low, and the rear shocks were two inches too short, putting the rear end way too low. And then there was the wiring!”

“It had that ‘midnight repair by the side of the road in Baja’ look to it. NOT sano.”

Richard decided to redo it, do it right. He stripped it down to the frame, repairing cracks, filling holes, and straightening or removing brackets until everything was perfect. Then he added a new rear loop and seat brackets.

Richard worked some magic further down too: “A few years ago I had a small batch of rectangular swingarms made for the Yamaha XS650 frame—which has the same mounting dimensions as the SR frame,” he tells us. “Fortunately I had one left.”

Mule’s set up the steering head to take the forks and triples from a 2006 Triumph Bonneville. That meant he could also install the Bonnie’s headlight brackets—pairing them with an LSL headlight for a ‘factory’ look. The forks themselves were sent off to Racetech for a rebuild and set of emulators.

Custom lower shock mounts were fabricated, allowing him to keep the shorter, adjustable Koni shocks—but allowing the Yamaha to sit a bit higher than stock in the rear.

The frame was then detabbed and powder coated a dark metallic grey, while the swingarm and triple clamps were shot with bright silver and a clear coat. Richard also swapped the stock side stand and mount out for a Mule kit—complete with a lightweight chromoly stand.

For the wheels, Richard used an 1975 XS650 front hub, but needed to move the bearings outboard to work with the wider forks. So he turned down the sides to accept custom bearing carriers. The rear already had a XT500 cush-drive hub—but it was trashed. So on went a lighter TT500 hub in perfect condition.

Both hubs were powder coated black, and laced up to matching black 18-inch Sun rims, with stainless steel spokes and nipples from Buchanan’s. “The 18-inch diameter theme was retained for a better road ride and tire selection than the normal 19-inch street tracker choice,” explains Richard, “but I widened the rims to 2.75 in front and 3.5 at the rear. This allows for a 120 front tire and a 140 rear.”

Braking upgrades include a custom front line from Crown Performance, hooked up to a Thruxton master cylinder and a 4-piston caliper from a R6, mounted on a custom bracket. The front disc is new too: it’s a floating Brembo unit from a Ducati, which turned out to be a perfect match for the XS650 hub’s bolt pattern.

Moving to the cockpit, Richard fitted a set of Mule stainless steel flat track bars, and a set of XS650 risers. The throttle is a quarter-turn number, sourced from a Ducati Hypermotard, and the levers are both Thruxton parts. Switchgear from Baja Designs wraps things up.

As for the bodywork, the fuel tank is stock, but the seat unit is from First Klass Glass. (“The highest quality fiberglass parts I’ve ever seen, and infinitely lighter than the one it replaced,” says Richard). The tail was sent to Saddlemen to be finished off with a custom seat pad.

David Tovar at Superbike Paint handled the color, but the guys opted for a slightly more maroon finish than traditional Yamaha red. “The TZ250 Yamaha stickers are the real thing though!”

As for the motor, Richard threw the book at it. “The cases and cylinder had been modified very poorly,” he says. “So I sourced a set of cases that looked as-new, surprising being that these motors are 38 years old.”

“A standard cylinder in perfect condition provided the basis for an increase from 500 to 540cc. The motor was ushered off to Mr. Ed Steffen in Hemet, California for a magic rebuild.”

The motor already had a Carillo rod and a Megacycle cam installed, both of which were in good nick, so those stayed. A new, stock ignition system went in though, along with a new 36mm round-slide Mikuni carb.

“The trend these days seems to be to remove everything between the carb slide and the debris flying off the rear tire, for the open airy look,” says Richard. “However, this bike will actually be ridden and ridden hard. A new stock plastic inner fender and K&N air filter ensure the motor will sleep well at night, knowing it’s protected.”

With the motor sorted, all that was left was to rewire the bike—complete with OEM coloring on the wires. A new battery tray holds the basics, along with a lightweight Lithium-ion battery from Shorai.

Notwithstanding the fact that it’s gorgeous, this is one of the most thoroughly reworked SR500s we’ve seen (if we listed every detail, it would fill a book).

Richard tells us it’s going to be hard to part with it—and we believe him. Who else wishes they were taking it home?